A stator frame constitutes the main body of an electrical motor and comprises interface surfaces for connecting other components and fixing them in position. The motor typically stands on mounting brackets to be securely mounted to a stationary support structure such as floor, work table, etc. The mounting brackets are attached to the underside of the stator frame, the stator frame comprising abutments to be supported on corresponding mounting interfaces on the mounting brackets. The shaft height of the motor is thereby partly defined by the mounting bracket height. The shaft heights of electrical motors are standardized, and there are motor series having a plurality of different stator frame sizes with equal shaft height. This means that a motor with a certain shaft height can be based on either a larger or a smaller stator frame. To meet the correct height according to the intended standards, different sizes of mounting brackets are needed. Motors based on bigger stator frames need lower mounting brackets and motors based on smaller stator frames need higher mounting brackets.
The mounting brackets typically have through holes for attachment to some support structure (floor) and to the stator frame, respectively. Not only the shaft height but also the pattern the through holes define for securing the mounting brackets to the support structure is standardized as well as the position of the hole pattern in relation to the motor shaft. A motor shaft typically comprises a shoulder separating two different shaft diameters, and the standards define the position of the hole pattern in relation to the axis of the motor shaft and the shoulder. Each stator frame size has a corresponding unique mounting bracket design, and the use of a correct mounting bracket article leads to a correct shaft height and to a correct hole pattern.
Since the mounting brackets are unique for each stator frame size the number of mounting bracket articles becomes large.